Electric-arc lamp



2 Sheets-Sheet 1.

(No Model.)

E. A. EDWARDS.

ELECTRIC ARC LAMP. I No. 485,537. Patented Nov. 1, 1892.

gnaw/Wm (No Model.) 2 Sheets-Sheet 2.

E. A. EDWARDS.

ELBGTRIO ARC LAMP.

Patented Nov. 1, 1892.

'ivrrn STAT S PATENT Fries.

EDGAR A. EDWARDS, OF CINCINNATI, OHIO.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 485,537, dated November1, 1892.

Application filed November 25, 1891. Serial No. 413,024. (No model-) Toall whom it may concern:

Be it known that I, EDGAR A. EDWARDS, a citizen of the United States,residing at Oincinnati, Hamilton county, State of Ohio, have inventedcertain new and useful Improvements in Focusing Electric-Arc Lamps, ofwhich the following is a specification.

My invention relates to electric lamps, and more particularly to thatclass of electric-arc lamps in which the arc can be maintained in asingle position for the purpose of focusing the light in order that itmay be projected in any desired direction by means of suitablereflectors arranged in connection with the lamp; and it has for itsobject to provide a simple, cheap, and effective lamp which is capableof withstanding shocks and jars without derangement and which shall bespecially adapted to be used on railway-trains as a head-light for theengine or other purposes; and to this end my invention consists in alamp embodying the various features of construction and arrangementsubstantially such as are hereinafter more particularly pointed out.

Referring to the accompanying drawings, Figure 1 is a front elevation ofthe preferred embodiment of my invention. Fig.2 is a side View of thesame. Fig. 3 is a diagram of the circuits. Fig. at is a rear perspectiveview showing the lamp in position in connection with the reflector.

It is well known that in the use of focusing arc lamps it is necessarythat the arc should be maintained in as nearly an absolute position aspossible in order that the best results may be obtained. While this is acomparatively-simple problem in the use of focusing arc lamps when thelamps are fixed upon a solid base, it is a much more difficult problemwhen the base is not so fixed, and especially when such a lamp isused,for instance, to furnish illumination fora locomotive headlight, asthe engine is subjected to a great deal of movement, and as aconsequence the lamp must be so constructed and adjusted as to be ableto sustain the shocks and jars due to the movements of the enginewithout danger of deranging the operative parts of the lamp orinterfering. with their adjustment. Furthermore, when the lamps are soused on locomotives it is necessary to make them of suitable dimensionand shape, so as to occupy but little space and to accommodate the partsto the reflector and reflector-case, and it is primarily with thisobject in view that I have produced the lamp which I am about todescribe, and while it is intended more especially for such use it isevident that the principles of construction and arrangement set forthmay be applied for other purposes and embodied in other devices by thoseskilled in the art and without departing from the spirit of theinvention. The lamp comprises a suitable base A, upon which is mountedthe support B for the operative parts of the device, and this support isbifurcated, so as to provide two arms 0 G, which furnish the means forsupporting the electrodes and operative mechanism. This support and basemay be of any material suitable for the purpose; but I preferably makeuse of metal having flanges and ribs to produce a practically-rigidsupport with the least Weight of material.

Upon one of the arms, as O, I mount a socket D, preferably insulatedfrom the arm by insulating material d, and this socket is provided withmeans for clamping it, as asetscrew 01'. Mounted in this socket is theelectrode-holder E, which in the present instance consists of a tube,preferably of brass, having slots c in its sides and serving as a guidefor the electrode F, which slides within the tube, while the slotsfurnish a means of determining at a glance the length of the electrodecontained in the holder.

Mounted on oneend of the electrode-holder is a bracket G, preferablyU-shaped and carrying on one of its arms a stop-piece g, preferably madeof copper and insulated from the bracket by some insulating material g,preferably of refractory material, as soapstone and the like. This stopreceives the end 0f the electrode F, which is usually tapered, andserves to support it and hold it in a fixed position with relation tothe other electrode about to be described, and at the same time saidelectrode as it is disintegrated gradually feeds, in the presentinstance by gravity, so as to maintain continuous contact between itsend and the stop. Mounted upon the other arm 0 of the support is theelectrode-holder Ii, having a construction similar to the other holder,being provided with slots IL. This electrode-holder in ust be arrangedso that it can move with relation to its complementary holder-as, forinstance, in establishing the arc-and in order to accomplish this Isupport this holder in the present instance upon flat flexible orspring-like arms I I, the ends of which are respectively secured to theelectrode-holder and to the arm 0 of the support. This construction, itwill be seen, will allow of a movement of the electrode-holder in aplanepassing through the arm and holder, but will prevent any lateralmovement of the holder outside of that plane. The electrodeholder II isprovided with means which will retain the electrode F within the holderand cause them to move together, and I have shown in the presentinstance one or more fingers J, which is preferably of copper or otherrefractory material, secured to the end of the holder and bearing on theelectrode near its point, and it will be seen that whatever movementsare imparted to the electrode-holder will be transmitted to theelectrode, so that the two will move in unison. The normal position ofthe electrodes when no current is passing is with their points or endportions in contact, and I have shown the electrodes arranged atsubstantially right angles to each other, as I have found fromexperience that not only does this arrangement furnish a convenient formfor use with parabolic or other reflectors, but that the are formedbetween the electrodes can be adjusted and maintained in the focal pointof the refiector, so that the greatest amount of light will bedistributed in the desired direction, as in this arrangement theelectrodes and their supports are so disposed as to interfere in theleast possible manner with the projection of the light-rays.

In order to establish the are and m aintain it when the lamp is inoperation, I provide a magnet K, which isshown inthe form of a pair ofsolenoids mounted on the arm O, and the cores K are connected byaheel-piece 7:, and to this heel-piece is connected a bar L,which isshown as clamped to the electrode-holder ll, so that any movementin thecores of the solenoids will be imparted positively to theelectrodeholder. In order to prevent too sudden movements in theelectrode-holder, due to changes or-makes or breaks in the circuit ofthe mag net, and also to aid in withstanding the shocks and jars towhich the lamp may be subjected, I provide a lever M,whieh ispivotallymounted in the frame and connected to the bar L by a rockingjoint on, and to the free end of thislever is attached one member of thedashpotN or equivalent retarding device, the other member being securedto the arm 0, as by a bracket N. To further regulate and control themovements of the electrodes, I provide a spring 0, which may be securedto the arm 0' and which is connected by means of an adj usting-screw Pto the lever M, suitable j amnuts 1) being provided to secure the screwin proper adjustment and to regulate the tension of the spring in itsaction on the lever M.

It is well known that in an ordinary are lamp the arc itself moves frompoint to point at the ends of the electrodes as they disintegrate, andwhile in the ordinary lamp this changing or jumping, as it is sometimescalled, is immaterial in a focusing-lamp it interferes with thesteadiness of the are and the uniform projection of the rays of lighttherefrom. In order to overcome this dillicult-y and to aid inmaintaining the arc in the focal point, I provide a magnet Q, which isarranged in a position to attract the electric arc and to confine it asnearly as possible to one position, and while this may be accomplishedin various ways I have shown the magnet as consisting of a bar securedto the clamping piece or socket D and having its bent end extendingthrough the yoke G, adjacent to the focal point of the carbons, andwhile this maybe a permanent magnet I have found that under theinfluence of the heat from the are the magnetism is impaired or evenvitiated, and I therefore provide the magnet Q with a coil R, which isconnected in the circuit of the lamp, so as to energize the magnetcontinuously when the lamp isin operation.

As before intimated, it is necessary that the arc should be accuratelyadjusted in the focal point of the reflector, and while the construction heretofore described is Well adapted for that purpose I findit advantageous to ad justably mount the reflector, so that the lamp andreflector may be accurately adjusted with relation to each other.

In Fig. 4 I have shown a simple and clfective means of carrying out thispart of themvention. In this construction S may be the sliding board ofan ordinary head-light, having a hinged support S", adapted to receivethe rim of the reflector T, which is shown as a parabolic reflector.Mounted on this sliding board is a support U, having a vertical standardXV, provided with a hole to to receive the screw X, which is attached tothe rearend of the reflector. This standard is split and is providedwith ears to, and the screw-bolt X is provided with a nut 00, by meansof which the reflector may be nicely adjusted on the standard, and thenthe cars to are secured in position by a suitable bolt to clamp thescrew and hold it firmly in position. In this wayI am enabled toaccurately adjust the reflector vertically and hold it in position. Thereflector is provided with openings t, through which the electrodes ofthe lamp and their holders are passed, so that the arc may be broughtinto the focal point, and in order to adjust this are laterally I attachthe support A of the lamp to the sliding board S by means of bolts a,passing through enlarged boltholes in the base of the support, and inthis way it will be seen I can readily adjust the lamp laterally andlongitudinally with rela- ICC tion tot-he reflector, while the latter isvertically adjusted by the means before described with relation to thelam p, and when the parts are once accurately adjusted they are held inposition against the shocks and jars to which they are subjected.Furthermore, by attaching the lamp and the reflector to the slidingboard they may both be removed from their position in the head-lightcase without disturbing the adjustment, or they can be adjusted beforeor after they are placed in the head-light case.

The circuits of the lamp are illustrated diagrammatically in Fig. 3, inwhich 1 indicates the plus binding-post, and 2 the negativebinding-post, which are secured to the frame, but insulated therefrom.From the plus binding-post a conductor 3 leads to the magnet R, and fromthence the current passes to the electrode-holder E, from whence itpasses directly to the electrode F through the point of contact of theelectrodes F and F to the electrode-holder H, and thence to the coils ofthe magnet K and to the negative bindingpost by the Wire 4:.

The operation of the lamp will be readily understood by those skilled inthe art and need not be described in detail, it being understood that inthe normal position with no current on the electrodes are in contact;but when the circuit is closed the magnet K is energized, attracting itscores and moving the electrode-holder l-I, so as to establish the arc,the flat springs I causing the same to move in a direction substantiallyparallel to the flattened portion of the arm 0, the dash-pot and springspreventing a too rapid movement, and also serving to aid the cores inholding the electrodes in proper position. At the same time the magnet Qis energized and attracts the electric arc, as before indicated, and Ifind that the lamp burns with great steadiness and regularity. It willbe understood, of course, that as the resistance of the arc increasesthrough the disintegration of the electrodes 2. In a focusingelectric-arc lamp, the com- 1 bination, with the carbon-holders arrangedat an angle to each other, of a positive carbon normally resting againsta fixed refractory axial stop and the negative carbon normally restingon a detaining-finger, substantially as described.

3. In a focusing electric-arc lamp, the combination, with a positivecarbon normally resting on an insulated metallic stop, of a negativecarbon normally resting against a detaining-finger, substantially asdescribed. 4. In a focusing electric-arc lamp, the combination, with thepositive-carbon holder, of an axial metallic stop supported thereby, but

insulated therefrom, and a negative-carbon holder carrying adetaining-finger for supporting the negative carbon, substantially asdescribed.

5. In a focusing electric-arc lamp, the combination, with theelectrode-holders arranged at an angle to each other, a positiveelectrode normally bearing against a fixed refractory stop, a negativeelectrode normally bearing against a detaining-finger, a magnet, andconnections for establishing and maintaining the arc, substantially asdescribed.

6. In a focusing electric-arc lamp, the combination, with theelectrode-holders arranged at an angle to each other, a positiveelectrode normally bearing against a fixed refractory stop, a negativeelectrode normally bearing against a detaining-finger, a magnet, andconnections between the magnetand thenegativeelectrode holder forestablishing and maintaining the are, substantially as described.

7. In a focusing electric-arc lamp, the combination, with thesupporting-frame, of an electrode-holder, fiat spring connecting theholder to the frame, a magnet, a bar connecting the core of the magnetto the holder, a lever pivotally connected to the bar, a dashpotconnected to the lever, and an adjustable spring, also connected to thelever, substantially as described.

8. In a focusing electric-arc lamp, the con1- bination, with anelectrode normally resting on a fixed refractory stop and an electrodenormally held by a detaining-finger at an angle to the first electrode,of a magnet arranged adjacent to the electrodes for directing the arc,substantially as described.

9. In a focusing electric-arc lamp, the combination of the positiveelectrode resting against the fixed refractory stop and a negativeelectrode resting against a detaining-finger and arranged at an angleto'the positive electrode, of a magnet, the coils of which are includedin the circuit of the lamp, the magnet being arranged in axial line withthe negative electrode, substantially as described.

10. In a focusing electric-arc lamp, the combination, with theelectrode-holder having a yoke supporting a stop, of anotherelectrodeholder arranged at an angle thereto and having adetaining-finger for the electrode and a magnet supported by the yokeadjacent to the point of contact of the electrodes, substantially asdescribed.

11. In an electric head-light, the combination, with the sliding board,of a reflector, a

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support mounted on the sliding board, con- I nections to the rear end ofthe retlector and adj ustablein said support, a lamp, also mounted onthe sliding board, and electrodes mounted on said arms and arranged atan angle to each other in the focal point of the reflector,substantially as described.

12. In an electric head-light, the combination, With the sliding board,of a reflector, a support mounted on the sliding board, connections tothe rear end of the reflector and adjustable in said support, alamp,alsomounted on the sliding board and having bifurcated arms embracing thereflector, and electrodes mounted on said arms and arranged at an angleto each other in the focal point of the refiector, substantially asdescribed.

13. In an electric head-light, the combination, with the slidingboard,asupportmounted thereon, and devices connected thereto forvertically adjusting the reflector, of a support a EDGAR A. EDWARDS.

Witnesses:

W. S. MOARTHUR, F. L. FREEMAN.

